5. Soaps and Detergents

Soaps & Detergents

Sodium or potassium salt of a carboxylic acid is known as Soap. They work most effectively in soap water. Detergents are sulfonates or ammonium salt of a long chain of carboxylic acid. They can work effectively on soft as well as hard water.

Cleansing actions of Soaps & Detergents
The cleansing action of soaps and detergents is due to the ability to minimize the surface tension of water, to emulsify oil or grease and hold them in a suspension of water. When soap dissolves in water, it forms soap anions and soap cations. The hydrophobic part of soaps and detergents are soluble in grease and the hydrophilic part is soluble in water.

Soaps & Micelle Formation

• When dirt and grease are mixed with soap water, soap molecules arrange them in tiny clusters known as Micelle.
• The hydrophilic part sticks to the water and forms the outer surface of the micelle and the hydrophobic part binds to oil and grease. 
• Soap micelles help to dissolve dirt and grease in water and clothes gets cleaned.
•  soap is a mixture of micelles.
• The magnesium and the calcium salts present in the hard water react with soap molecules to form in soluble product called scum.
• This scum create difficulty in cleansing action.
• By use of detergent, insoluble scum is not formed with hard water and clothes get cleaned effectively.